Quick Search:    advanced search

GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help

This Article Résumé Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Barkov, A. Y. Articles by Tarkian, M. Search for Related Content GeoRef GeoRef Citation

COMPOSITIONAL VARIATIONS IN OULANKAITE AND A NEW SERIES OF ARGENTOAN OULANKAITE FROM THE LUKKULAISVAARA LAYERED INTRUSION, NORTHERN RUSSIAN KARELIA

Andrei Y. Barkov^1,, Michael E. Fleet^1,, Robert F. Martin^2, and Mahmud Tarkian^3,

¹ Department of Earth Sciences, University of Western Ontario, London, Ontario N6A 5B7, Canada
² Department of Earth and Planetary Sciences, McGill University, 3450 University Street, Montreal, Quebec H3A 2A7, Canada
³ Institute of Mineralogy and Petrology, University of Hamburg, Grindelallee 48, D-20146 Hamburg, Germany

E-mail addresses: abarkov{at}uwo.ca, mfleet{at}uwo.ca, bobm{at}eps.mcgill.ca, mtark{at}mineralogie.uni-hamburg.de

Oulankaite, a complex base- and precious-metal stannosulfotelluride from the Nadezhda deposit in the Lukkulaisvaara layered intrusion, northern Karelia, northwestern Russia, exhibits a considerable variation in composition. At the type locality, this unique species of platinum-group mineral (PGM) is associated with various base-metal sulfides and PGM in hydrothermally altered pods and stringers of coarse-grained to pegmatitic gabbronorite, located within a sill-like body of microgabbronorite. Covariations in contents of (Pd + Pt) and (Cu + Fe + Ag) are observed in Ag-poor oulankaite (<0.1 wt.% Ag) and in a new compositional series of argentoan oulankaite (up to 1.52 Ag atoms per formula unit, apfu: atoms = 14). On the basis of the new data, we suggest a revised generalized formula for oulankaite: (Pd,Pt)_5+x(Cu,Fe,Ag)_4–xSnTe₂S₂, with 0 x < 1. The formula of the Ag-dominant analogue of oulankaite is similar: (Pd,Pt)_5+x(Ag,Cu,Fe)_4–xSnTe₂S₂, with 0 x < 1. Two different mechanisms of substitution exist in argentoan oulankaite, Ag-for-Cu and Pd-for-(Cu+Ag), whereas the composition of Ag-poor oulankaite is dominated by Pd-for-Cu substitution. Argentoan oulankaite ranges up to (Pd_5.31Pt_0.17)_5.48(Ag_1.52Cu_1.27Fe_0.63)_3.42Sn_1.03Te_2.09S_1.98, which is likely an unnamed species of PGM. Micro-inclusions of Cl-rich ferropargasite (up to 3.25 wt.% Cl) occur in argentoan oulankaite and Ag-poor oulankaite. The argentoan oulankaite solid-solution probably formed from microvolumes of a late-stage liquid or fluid rich in Pd, Ag, Cu, Sn, Te, and S, which is consistent with the Pd–(Pt)–Ag mineralization in the Nadezhda deposit.

Keywords: oulankaite, solid solution, sulfotelluride, platinum-group elements, platinum-group minerals, layered intrusion, Lukkulaisvaara, Russian Karelia, Baltic Shield.

This article has been cited by other articles:

				G. S. Henderson and Y. Pan S3: SULFIDES, STRUCTURES AND SYNCHROTRON LIGHT A TRIBUTE TO MICHAEL E. FLEET: PREFACE Can Mineral, October 1, 2005; 43(5): 1449 - 1456. [Full Text] [PDF]

				A. Y. Barkov, M. E. Fleet, R. F. Martin, and T. T. Alapieti ZONED SULFIDES AND SULFARSENIDES OF THE PLATINUM-GROUP ELEMENTS FROM THE PENIKAT LAYERED COMPLEX, FINLAND Can Mineral, April 1, 2004; 42(2): 515 - 537. [Abstract] [Full Text] [PDF]